Pre-service teachers are increasingly engaging with generative AI (GenAI) tools such as ChatGPT. This mixed-methods study explores how Irish pre-service primary teachers use GenAI, alongside their perceptions of its opportunities, challenges, ethical implications, and professional development needs. The analysis considers variables including year of study and placement-related stress. Quantitative data were collected from 190 participants, complemented by qualitative interviews with four student teachers—one from each year group.

Findings reveal a clear developmental trajectory in GenAI adoption. Usage increases from Year 1 to Year 3. Patterns of use also shift: while first-year students primarily engage with GenAI for personal tasks, fourth-year students increasingly apply it to lesson planning and classroom resource creation. Initial scepticism and ethical concerns are most significant in Year 1 and diminish over time, while perceived opportunities peak in Year 3. The need for targeted professional development remains consistent across all years. All interviewees highlighted a strong demand for clearer institutional guidance. Notably, placement-related stress appears to influence GenAI use most strongly in Year 3, with students under higher stress levels reporting more frequent use. These findings underscore the urgent need for professional development and institutional policies to support the integration of GenAI in teacher education.